# 11.29     What do you understand by   (a) inert pair effect

On moving down the group in the periodic table, the tendency of $s$-orbital electron to participate in bonding is decreased. This effect is known as the inert pair effect. For example, in group 13 element ($ns^2,np^1$)the stability of +1 oxidation is more than the +2 oxidation state due to the poor shielding of the $ns^2$ electrons by the $d$ and $f$ electron, as a result, $ns^2$electrons are strongly held by the nucleus.